/*
 *   FUSE: Filesystem in Userspace
 *     Copyright (C) 2001-2007  Miklos Szeredi <miklos@szeredi.hu>
 *
 *       This program can be distributed under the terms of the GNU GPL.
 *         See the file COPYING.
 *
 */

#define FUSE_USE_VERSION  26
   
  #include <fuse.h>
  #include <stdio.h>
  #include <string.h>
  #include <errno.h>
  #include <fcntl.h>
  #include <unistd.h>
  #include <dirent.h>
   
  static const char *hello_str = "user_filesystem\n";
  static const char *hello_path = "/hello";
  
  static int hello_getattr(const char *path, struct stat *stbuf)
  {
      int res = 0;
      memset(stbuf, 0, sizeof(struct stat));
      if(strcmp(path, "/") == 0) {
          stbuf->st_mode = S_IFDIR | 0777;
          stbuf->st_nlink = 3;
      }
      else if(strcmp(path, hello_path) == 0) {
          stbuf->st_mode = S_IFREG | 0444;
          stbuf->st_nlink = 1;
          stbuf->st_size = strlen(hello_str);
      }
      else
 	res = lstat(path, stbuf);
 
      return res;
  }
  
  static int hello_readdir(const char *path, void *buf, fuse_fill_dir_t filler,
                           off_t offset, struct fuse_file_info *fi)
  {
      (void) offset;
      (void) fi;
  
      if(strcmp(path, "/") != 0)
          return -ENOENT;
  
      filler(buf, ".", NULL, 0);
      filler(buf, "..", NULL, 0);
      filler(buf, hello_path + 1, NULL, 0);
  
      return 0;
  }
  
  static int hello_open(const char *path, struct fuse_file_info *fi)
  {
      if(strcmp(path, hello_path) != 0)
          return -ENOENT;
  
      if((fi->flags & 3) != O_RDONLY)
          return -EACCES;
  
      return 0;
  }
  
  static int hello_read(const char *path, char *buf, size_t size, off_t offset,
                        struct fuse_file_info *fi)
  {
      size_t len;
      (void) fi;
      if(strcmp(path, hello_path) != 0)
          return -ENOENT;
  
      len = strlen(hello_str);
      if (offset < len) {
          if (offset + size > len)
              size = len - offset;
          memcpy(buf, hello_str + offset, size);
      } else
          size = 0;
  
      return size;
  }

  static struct fuse_operations hello_oper = {
      .getattr   = hello_getattr,
      .readdir = hello_readdir,
      .open   = hello_open,
      .read   = hello_read,
  };
  
  int main(int argc, char *argv[])
  {
      return fuse_main(argc, argv, &hello_oper, NULL);
  }
